scholarly journals Presence and characteristics of sorbitol-negative Escherichia coli O157 in healthy sheep faeces

2008 ◽  
Vol 52 (No. 7) ◽  
pp. 301-307 ◽  
Author(s):  
H. Turutoglu ◽  
D. Ozturk ◽  
L. Guler ◽  
F. Pehlivanoglu
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Shiga Toxin ◽  
Human Pathogens ◽  
Isolation Rate ◽  
E Coli ◽  
Awassi Sheep ◽  
Healthy Sheep

The presence of sorbitol-negative <i>Escherichia coli</i> O157 was investigated in healthy Awassi sheep faeces from 175 randomly selected animals in Burdur province of Turkey. Out of 175 animals, 16 (9.1%) were faecal shedding of sorbitol-negative <i>E. coli</i> O157. Out of the 15 flocks included in the study, 7 (47%) had at least one sheep positive for sorbitol-negative <i>E. coli</i> O157. The isolation rate of sorbitol-negative <i>E. coli</i> O157 ranged from 8.3 to 60% among the animals tested in the flocks. A total of 16 ovine sorbitol-negative <i>E. coli</i> O157 strains were characterized by a multiplex PCR. Results showed that 6 (37.7%) strains carried <i>stx1</i> gene, 3 (18.8%) <i>stx2</i> gene and 1 (6.3%) both <i>stx1</i> and <i>stx2</i> genes. Intimin (<i>eaeA</i>) gene was detected in 4 (25%) of the strains. None of the strains encoding for <i>stx</i> genes was positive for <i>eaeA</i> gene. The results demonstrate that the majority of sorbitol-negative <i>E. coli</i> O157 strains (62.5%) isolated from Awassi sheep in Burdur province of Turkey are Shiga toxin-producing <i>E. coli</i> that have a potential as human pathogens.

scholarly journals Prevalence of a Gene Encoding Adhesin Involved in Diffuse Adherence among Escherichia Coli Isolates in Pigs with Postweaning Diarrhea or Edema Disease

2003 ◽  
Vol 15 (4) ◽  
pp. 378-381 ◽  
Author(s):  
Seung-Kwon Ha ◽  
Changsun Choi ◽  
Chanhee Chae
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Coli Strain ◽  
Isolation Rate ◽  
Gene Encoding ◽  
Edema Disease ◽  
E Coli ◽  
Heat Stable ◽  
Fimbrial Adhesins ◽  
Postweaning Diarrhea

A total of 604 Escherichia coli strains isolated from weaned pigs with diarrhea or edema disease on 653 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of 5 fimbriae (F4, F5, F6, F18, and F41), 3 heat-stable (STa, STb, and EAST1) and 1 heat-labile (LT) enterotoxin, and Shiga toxin 2e (Stx2e) genes. Forty-five (7.5%) of the 604 E. coli isolates carried the gene for AIDA. Of these 45 isolates, 5 (11.1%) carried EAST1 genes only, 1 (2.2%) carried genes for at least one of the fimbrial adhesins, 12 (26.7%) carried genes for at least one of the toxins, and 27 (60%) carried genes for at least one of the fimbrial adhesins and toxins. Fifty-one percent of strains that carried AIDA genes carried Stx2e genes, and 40% of strains that carried AIDA genes carried F18ab. The isolation rate of enterotoxigenic E. coli strain carrying genes for AIDA was 87%, and the isolation rate of Shiga toxin-producing E. coli strain carrying genes for AIDA was 49%. AIDA may represent an important virulence determinant in pigs with postweaning diarrhea or edema disease.

scholarly journals Subtypes of the Plasmid-Encoded Serine Protease EspP in Shiga Toxin-Producing Escherichia coli: Distribution, Secretion, and Proteolytic Activity

2007 ◽  
Vol 73 (20) ◽  
pp. 6351-6359 ◽  
Author(s):  
Jens Brockmeyer ◽  
Martina Bielaszewska ◽  
Angelika Fruth ◽  
Marie Luise Bonn ◽  
Alexander Mellmann ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Serine Protease ◽  
Proteolytic Activity ◽  
Shiga Toxin ◽  
Point Mutations ◽  
Coagulation Factor ◽  
Factor V ◽  
Human Pathogens ◽  
E Coli ◽  
Bona Fide

ABSTRACT We investigated the prevalence, distribution, and structure of espP in Shiga toxin-producing Escherichia coli (STEC) and assessed the secretion and proteolytic activity of the encoded autotransporter protein EspP (extracellular serine protease, plasmid encoded). espP was identified in 56 of 107 different STEC serotypes. Sequencing of a 3,747-bp region of the 3,900-bp espP gene distinguished four alleles (espPα, espPβ, espPγ, and espPδ), with 99.9%, 99.2%, 95.3%, and 95.1% homology, respectively, to espP of E. coli O157:H7 strain EDL933. The espPβ, espPγ, and espPδ genes contained unique insertions and/or clustered point mutations that enabled allele-specific PCRs; these demonstrated the presence of espPα, espPβ, espPγ, and espPδ in STEC isolates belonging to 17, 16, 15, and 8 serotypes, respectively. Among four subtypes of EspP encoded by these alleles, EspPα (produced by enterohemorrhagic E. coli [EHEC] O157:H7 and the major non-O157 EHEC serotypes) and EspPγ cleaved pepsin A, human coagulation factor V, and an oligopeptide alanine-alanine-proline-leucine-para-nitroaniline, whereas EspPβ and EspPδ either were not secreted or were proteolytically inactive. The lack of proteolysis correlated with point mutations near the active serine protease site. We conclude that espP is widely distributed among STEC strains and displays genetic heterogeneity, which can be used for subtyping and which affects EspP activity. The presence of proteolytically active EspP in EHEC serogroups O157, O26, O111, and O145, which are bona fide human pathogens, suggests that EspP might play a role as an EHEC virulence factor.

Rapid and Reliable Detection of Shiga Toxin–Producing Escherichia coli by Real-Time Multiplex PCR

2012 ◽  
Vol 75 (4) ◽  
pp. 643-650 ◽  
Author(s):  
KELLY S. ANKLAM ◽  
KAUSHI S. T. KANANKEGE ◽  
TINA K. GONZALES ◽  
CHARLES W. KASPAR ◽  
DÖRTE DÖPFER
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Real Time ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Health Concern ◽  
E Coli ◽  
Reliable Detection ◽  
Pcr Assays

Escherichia coli O26, O45, O103, O111, O121, O145, and O157 are the predominant Shiga toxin–producing E. coli (STEC) serogroups implicated in outbreaks of human foodborne illness worldwide. The increasing prevalence of these pathogens has important public health implications. Beef products have been considered a main source of foodborne human STEC infections. Robust and sensitive methods for the detection and characterization of these pathogens are needed to determine prevalence and incidence of STEC in beef processing facilities and to improve food safety interventions aimed at eliminating STEC from the food supply. This study was conducted to develop Taqman real-time multiplex PCR assays for the screening and rapid detection of the predominant STEC serogroups associated with human illness. Three serogroup-specific assays targeted the O-antigen gene clusters of E. coli O26 (wzy), O103 (wzx), and O145 (wzx) in assay 1, O45 (wzy), O111 (manC), and O121 (wzx) in assay 2, and O157 (rfbE) in assay 3. The uidA gene also was included in the serogroup-specific assays as an E. coli internal amplification control. A fourth assay was developed to target selected virulence genes for Shiga toxin (stx1 and stx2), intimin (eae), and enterohemolysin (ehxA). The specificity of the serogroup and virulence gene assays was assessed by testing 100 and 62 E. coli strains and non–E. coli control strains, respectively. The assays correctly detected the genes in all strains examined, and no cross-reactions were observed, representing 100% specificity. The detection limits of the assays were 103 or 104 CFU/ml for pure cultures and artificially contaminated fecal samples, and after a 6-h enrichment period, the detection limit of the assays was 100 CFU/ml. These results indicate that the four real-time multiplex PCR assays are robust and effective for the rapid and reliable detection of the seven predominant STEC serogroups of major public health concern and the detection of their virulence genes.

Method for the Detection of Priority Shiga Toxin–Producing Escherichia coli in Beef Trim

2013 ◽  
Vol 76 (10) ◽  
pp. 1689-1696 ◽  
Author(s):  
GEORGE HUSZCZYNSKI ◽  
MARTINE GAUTHIER ◽  
SAM MOHAJER ◽  
ALEXANDER GILL ◽  
BURTON BLAIS
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Shiga Toxin ◽  
Limit Of Detection ◽  
Turnaround Time ◽  
Direct Plating ◽  
E Coli ◽  
Agar Media ◽  
Pcr Techniques ◽  
Positive Results

A method has been developed for the detection in beef trim of priority Shiga toxin–producing E. coli (STEC) strains, defined as E. coli possessing the virulence factors stx1 and/or stx2 and intimin (eae), with O serogroups O26, O45, O103, O111, O121, O145, or O157. The method is based on recovery of the target bacteria by overnight enrichment in a broth optimized for recovery of O157 and non-O157 STEC, followed by screening using multiplex PCR techniques targeting (i) stx1, stx2, and eae (STE PCR) and (ii) gene sequences associated with the seven priority O serogroups (Poly O PCR), and then direct plating of broth samples positive in both STE and Poly O PCR onto Rainbow agar. Colonies on agar media were screened batchwise for STEC by the STE PCR, and presumptive isolates were characterized using a multiplex PCR and cloth-based hybridization array system targeting key virulence and O serogroup-specific markers. Using one representative strain of each priority O serogroup individually inoculated in beef trim samples, the method exhibited a limit of detection approaching 1 to 2 viable STEC cells per 65 g. None of the uninoculated trim samples produced positive results with either of the screening PCR procedures or on analysis of colonies recovered on plating media. STEC-negative samples were readily identified by screening PCR within 24 h, with a turnaround time of fewer than 4 days for confirmation of positives. The inclusivity and exclusivity characteristics of the screening PCR techniques were verified using a total of 65 different priority STEC strains: 24 nonpriority STEC, 15 non-STEC bacteria, and only those strains bearing the targeted characteristics produced screening PCR-positive results.

scholarly journals ppGpp and cytotoxicity diversity in Shiga toxin-producingEscherichia coli(STEC) isolates

2017 ◽  
Vol 145 (11) ◽  
pp. 2204-2211 ◽  
Author(s):  
A. E. STELLA ◽  
D. LUZ ◽  
R. M. F. PIAZZA ◽  
B. SPIRA
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phenotypic Characteristics ◽  
Guanosine Tetraphosphate ◽  
E Coli ◽  
Healthy Sheep ◽  
Food Pathogen ◽  
Low Levels ◽  
High Cytotoxicity ◽  
Genotypic Characteristics

SUMMARYShiga toxin-producingEscherichia coli(STEC) is a known food pathogen, which main reservoir is the intestine of ruminants. The abundance of different STEC lineages in nature reflect a heterogeneity that is characterised by the differential expression of certain genotypic characteristics, which in turn are influenced by the environmental conditions to which the microorganism is exposed. Bacterial homeostasis and stress response are under the control of the alarmone guanosine tetraphosphate (ppGpp), which intrinsic levels varies across theE. colispecies. In the present study, 50 STEC isolates from healthy sheep were evaluated regarding their ppGpp content, cytotoxicity and other relevant genetic and phenotypic characteristics. We found that the level of ppGpp and cytotoxicity varied considerably among the examined strains. Isolates that harboured thestx2 gene were the least cytotoxic and presented the highest levels of ppGpp. Allstx2 isolates belonged to phylogroup A, while strains that carriedstx1 or bothstx1 andstx2 genes pertained to phylogroup B1. All but twostx2 isolates belonged to thestx2b subtype. Strains that belonged to phylogroup B1 displayed on average low levels of ppGpp and high cytotoxicity. Overall, there was a negative correlation between cytotoxicity and ppGpp.

scholarly journals Presence of Escherichia coli O157 and O157:H7 in raw milk and Van herby cheese

2015 ◽  
Vol 59 (4) ◽  
pp. 511-514 ◽  
Author(s):  
Yakup Can Sancak ◽  
Hakan Sancak ◽  
Ozgur Isleyici
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Drug Administration ◽  
Shiga Toxin ◽  
Raw Milk ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Emerging Pathogens ◽  
E Coli ◽  
Milk Samples

Abstract The Shiga toxin-producing Escherichia coli (STEC) strains are currently considered important emerging pathogens threatening public health. Among Shiga toxin-producing Escherichia coli, E. coli O157:H7 strains have emerged as important human pathogens. This study was conducted to determine the presence of Escherichia coli O157 and O157:H7 in raw milk samples and Van herby cheese samples. For this purpose, 100 samples of raw milk were collected and 100 samples of herby cheese sold for consumption in Van province in Turkey were obtained from grocers and markets in order to detect the presence of Escherichia coli O157 and O157:H7. The method of E. coli O157 and O157:H7 isolation proposed by the Food and Drug Administration (FDA) was used. E. coli O157 in raw milk and herby cheese samples was found in 11% and 6% of samples respectively, and E. coli O157:H7 was found in 2% of herby cheese samples. No E. coli O157:H7 was detected in raw milk samples. This study showed that raw milk was contaminated with E. coli O157 and herby cheese was contaminated with both E. coli O157 and E. coli O157:H7; therefore, herby cheese poses a serious risk to public health.

Evidence of Non-O157 Shiga Toxin–Producing Escherichia coli in the Feces of Meat Goats at a U.S. Slaughter Plant

2013 ◽  
Vol 76 (9) ◽  
pp. 1626-1629 ◽  
Author(s):  
M. E. JACOB ◽  
D. M. FOSTER ◽  
A. T. ROGERS ◽  
C. C. BALCOMB ◽  
X. SHI ◽  
...  
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Shiga Toxin ◽  
Virulence Genes ◽  
Southeastern United States ◽  
Human Pathogens ◽  
Fecal Samples ◽  
E Coli ◽  
Meat Goats ◽  
Two Samples

Shiga toxin–producing Escherichia coli (STEC) are important human pathogens, and attention to non-O157 serogroups has increased in recent years. Although cattle are normally considered the primary reservoir for STEC, recent illnesses associated with goat contact have indicated that these animals are important potential reservoirs for the organisms. The prevalence of STEC, particularly non-O157 serogroups, in U.S. goats has not been well described. Our objective was to determine the prevalence of six major non-O157 STEC serogroups in the feces of meat goats. Rectal contents from 296 goats were collected postevisceration at a slaughter plant in the southeastern United States over 9 days during a 12-week period from August through October 2012. Samples were enriched in E. coli broth, and DNA was extracted and used as template in an 11-gene multiplex PCR that detected six non-O157 serogroups (O26, O45, O103, O121, O111, and O145) and virulence genes. Samples were considered positive when at least one non-O157 STEC serotype was present with either stx1 or stx2. All six non-O157 serogroups were detected by PCR in our samples, and 14.5% of samples were positive for at least one serogroup. Prevalence of O26 was highest, with 6.4% of goat fecal samples positive. The prevalence of O45 was 3.4%, O103 was 4.4%, O111 was 4.1%, O121 was 1.4%, and O145 was 3.0%. Twenty-two (7.4%) of 296 fecal samples had more than one non-O157 serogroup detected in the feces. Two samples had evidence of three non-O157 STEC serogroups. Goats appear to be an important reservoir for non-O157 STEC, and further work to understand the characteristics, epidemiology, and ecology of STEC in these animals is warranted.

Growth of Escherichia coli O157:H7, Non-O157 Shiga Toxin–Producing Escherichia coli, and Salmonella in Water and Hydroponic Fertilizer Solutions

2016 ◽  
Vol 79 (12) ◽  
pp. 2179-2183 ◽  
Author(s):  
ANGELA SHAW ◽  
KARA HELTERBRAN ◽  
MICHAEL R. EVANS ◽  
CHRISTOPHER CURREY
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Water System ◽  
The United States ◽  
Plain Water ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
E Coli ◽  
Fertilizer Solution ◽  
Fertilizer Solutions

ABSTRACT The desire for local, fresh produce year round is driving the growth of hydroponic growing systems in the United States. Many food crops, such as leafy greens and culinary herbs, grown within hydroponics systems have their root systems submerged in recirculating nutrient-dense fertilizer solutions from planting through harvest. If a foodborne pathogen were introduced into this water system, the risk of contamination to the entire crop would be high. Hence, this study was designed to determine whether Escherichia coli O157:H7, non-O157 Shiga toxin–producing E. coli, and Salmonella were able to survive and reproduce in two common hydroponic fertilizer solutions and in water or whether the bacteria would be killed or suppressed by the fertilizer solutions. All the pathogens grew by 1 to 6 log CFU/ml over a 24-h period, depending on the solution. E. coli O157:H7 reached higher levels in the fertilizer solution with plants (3.12 log CFU/ml), whereas non-O157 Shiga toxin–producing E. coli and Salmonella reached higher levels in the fertilizer solution without plants (1.36 to 3.77 log CFU/ml). The foodborne pathogens evaluated here survived for 24 h in the fertilizer solution, and populations grew more rapidly in these solutions than in plain water. Therefore, human pathogens entering the fertilizer solution tanks in hydroponic systems would be expected to rapidly propagate and spread throughout the system and potentially contaminate the entire crop.

scholarly journals Virulence Potential of Activatable Shiga Toxin 2d–Producing Escherichia coli Isolates from Fresh Produce

2015 ◽  
Vol 78 (11) ◽  
pp. 2085-2088 ◽  
Author(s):  
ANGELA R. MELTON-CELSA ◽  
ALISON D. O'BRIEN ◽  
PETER C. H. FENG
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Fresh Produce ◽  
Vero Cells ◽  
Human Pathogens ◽  
E Coli ◽  
Intestinal Mucus ◽  
Virulence Potential ◽  
Beef Products ◽  
Uremic Syndrome

Shiga toxin (Stx)–producing Escherichia coli (STEC) strains are food- and waterborne pathogens that are often transmitted via beef products or fresh produce. STEC strains cause both sporadic infections and outbreaks, which may result in hemorrhagic colitis and hemolytic uremic syndrome. STEC strains may elaborate Stx1, Stx2, and/or subtypes of those toxins. Epidemiological evidence indicates that STEC that produce subtypes Stx2a, Stx2c, and/or Stx2d are more often associated with serious illness. The Stx2d subtype becomes more toxic to Vero cells after incubation with intestinal mucus or elastase, a process named “activation.” Stx2d is not generally found in the E. coli serotypes most commonly connected to STEC outbreaks. However, STEC strains that are stx2d positive can be isolated from foods, an occurrence that gives rise to the question of whether those food isolates are potential human pathogens. In this study, we examined 14 STEC strains from fresh produce that were stx2d positive and found that they all produced the mucus-activatable Stx2d and that a subset of the strains tested were virulent in streptomycin-treated mice.

scholarly journals Multiplex PCR for Enterotoxigenic, Attaching and Effacing, and Shiga Toxin-Producing Escherichia coli Strains from Calves

1998 ◽  
Vol 36 (6) ◽  
pp. 1795-1797 ◽  
Author(s):  
Sophia M. Franck ◽  
Brad T. Bosworth ◽  
Harley W. Moon
Keyword(s):  
Escherichia Coli ◽  
Multiplex Pcr ◽  
Shiga Toxin ◽  
Shiga Toxins ◽  
E Coli ◽  
Heat Stable ◽  
Genes Encoding

A multiplex PCR was developed to identify enterotoxigenic, attaching and effacing, and Shiga toxin-producing Escherichia coli strains by amplifying genes encoding K99 and F41 fimbriae, heat-stable enterotoxin a, intimin, and Shiga toxins 1 and 2. This multiplex PCR was specific and sensitive. It will be useful for identification of E. coli strains which cause diarrhea in calves.

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